Bristle-thighed Curlew (Numenius tahitiensis)

Common Name: Bristle-thighed Curlew

Scientific Name: Numenius tahitiensis
SizeDietRange in HawaiiStatus in Hawaii
7 in. - 8 in.crustaceans, insects, worms, and mollusksCommon on all IslandsLeast Concern

The bristle-thighed curlew, also known as Numenius tahitiensis, is a rare and enigmatic bird that is known for its distinctive appearance and fascinating life history. This bird was discovered wintering on South Pacific islands in 1769, but its nesting grounds were not found until almost 180 years later in the late 1940s, in a few hilly areas of western Alaska.

However, did you know that the bristle-thighed curlew is also a non-breeding visitor to Hawaii? Despite its rarity, this bird can be spotted on the sandy beaches and rocky shores of Hawaii during the winter months.

In this article, we will explore the world of the bristle-thighed curlew and discover what makes this bird so special, including its unique migration patterns, habitat preferences, and behavior when it visits the beautiful islands of Hawaii.

Bristle-thighed Curlew

Appearance

Bristle-thighed perching
Bristle-thighed Curlew perching | image by Dominic Sherony via Flickr | CC BY-SA 2.0

The Bristle-thighed Curlew is a unique bird with distinct features. It has a long, downward-curved bill that measures around 4-5 inches in length. With a wingspan of approximately 28-32 inches, this curlew is a medium-sized shorebird.

It has a mottled brown plumage, a streaked breast, and a distinctive white eyeline that stands out on its face. The Bristle-thighed Curlew is known for the bristly feathers on its upper legs, which give it its name.

Diet

The Bristle-thighed Curlew has a diverse diet that primarily consists of invertebrates such as insects, worms, and crustaceans. During its breeding season in the Arctic, it also feeds on a variety of plant materials including berries and seeds.

This curlew has a unique foraging behavior, using its long bill to probe into the mud and soil to extract prey. It is well adapted to its coastal habitat and relies on the abundance of food resources found in marshes, estuaries, and tidal flats.

Nesting

The Bristle-thighed Curlew constructs its nest on the ground in the tundra regions of Alaska and Siberia. The female curlew selects a suitable nesting site and builds a shallow depression lined with grasses, leaves, and other vegetation.

She typically lays a clutch of four eggs, which are camouflaged to blend in with the surroundings. Both the male and female take turns incubating the eggs for about 25 to 27 days until they hatch.

Once the chicks hatch, they are precocial, meaning they are able to move and feed shortly after birth. The adults closely guard and care for the chicks, teaching them foraging skills until they are independent enough to migrate south for the winter.

Behavior

Bristle-thighed curlew standing
Bristle-thighed curlew standing | image by ericdalecreative via Flickr

The Bristle-thighed Curlew exhibits fascinating behavior throughout its lifecycle. During the breeding season, these birds perform intricate aerial displays, including soaring, calling, and diving, to attract mates and establish territories.

They are known for their long-distance migratory behavior, traveling thousands of miles between their breeding grounds in Alaska and Siberia to their wintering areas in the Pacific islands, including Hawaii and Polynesia.

Bristle-thighed Curlews are highly territorial during the breeding season, defending their nesting sites from intruders. They communicate through various vocalizations, including melodic calls and alarm signals. These birds are primarily diurnal, being active during the day, and rely on their keen eyesight and long, curved bills to detect and capture their prey.

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Feeding behavior of the Bristle-thighed Curlew involves probing the soft ground with their bills to search for invertebrates, such as insects, worms, crustaceans, and small mollusks. They also consume berries and other plant materials during the non-breeding season. These birds are known for their resourcefulness in finding food sources, often utilizing intertidal zones and mudflats for foraging.

During migration, Bristle-thighed Curlews undertake remarkable journeys, flying long distances across open ocean without rest. They navigate using celestial cues, landmarks, and their innate sense of direction. This species has faced challenges due to habitat loss, hunting, and climate change, making conservation efforts crucial for their survival.

Habitat

The Bristle-thighed Curlew inhabits a variety of habitats across its range. During the breeding season, these curlews prefer nesting in open tundra regions, such as Arctic meadows and grassy slopes in Alaska and Siberia. They select sites with sparse vegetation and good visibility, allowing them to keep an eye out for predators and intruders.

During migration, Bristle-thighed Curlews rely on coastal areas, including mudflats, estuaries, and intertidal zones, where they find abundant food resources. These habitats provide rich feeding grounds for the curlews, as they probe the soft ground for invertebrates and forage in shallow water for small crustaceans and mollusks.

In their non-breeding range, Bristle-thighed Curlews are known to utilize a variety of habitats, including sandy beaches, coastal wetlands, and grassy plains. They are particularly notable for their presence in the Pacific islands, including Hawaii and Polynesia, where they find suitable foraging areas and resting sites during the winter months.

Range

The Bristle-thighed Curlew is a regular winter visitor to the Hawaiian Islands. While it primarily breeds in Alaska and Siberia, it undertakes a remarkable migration across the Pacific to spend the non-breeding season in Hawaii. These curlews can be found on all major Hawaiian islands, including Oahu, Maui, Kauai, and Hawaii Island.

They are often observed in coastal areas, wetlands, and grassy fields, where they forage for food and rest during their stay. The presence of the Bristle-thighed Curlew in Hawaii is a testament to the importance of the islands as a wintering habitat for migratory shorebirds.

Conservation Status

Flock of bristle-thighed curlew
Flock of bristle-thighed curlew | image by ericdalecreative via Flickr

The Bristle-thighed Curlew is classified as “Near Threatened” by the International Union for Conservation of Nature (IUCN). This status reflects the species’ susceptibility to various threats, including habitat loss, degradation, and disturbance. Human activities such as coastal development and climate change pose significant challenges to its breeding and wintering habitats.

With a small and declining population size, the Bristle-thighed Curlew requires conservation efforts to protect its critical breeding grounds in Alaska and Siberia, as well as its wintering areas in Hawaii.

Ongoing research, monitoring, and habitat management initiatives aim to gain a better understanding of the species and implement effective conservation measures. The near-threatened status of the Bristle-thighed Curlew emphasizes the importance of concerted actions to preserve this migratory shorebird and its vital habitats.

Interesting Facts

1. Unique breeding grounds

The Bristle-thighed Curlew has one of the most restricted breeding ranges among shorebirds, nesting only in the remote and rugged terrain of Alaska and eastern Siberia.

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2. Feathered “bristles”

The Bristle-thighed Curlew gets its name from the distinct bristles that can be seen on its upper thighs. These bristles are thought to play a role in courtship displays and territorial defense.

3. Wintering in Hawaii

The Bristle-thighed Curlew is known to winter exclusively in the Hawaiian Islands, making it a rare and special visitor to these tropical islands. It can be found on all the major Hawaiian islands during the winter months.

4. Population decline

The Bristle-thighed Curlew population is declining, primarily due to habitat loss and degradation. Conservation efforts are focused on protecting and restoring its critical breeding and wintering habitats.

5. Migratory challenges

The Bristle-thighed Curlew faces numerous challenges during its long migration, including adverse weather conditions, predation, and habitat loss along its flyway.

Frequently Asked Questions

1. How long does the Bristle-thighed Curlew live?

The lifespan of the Bristle-thighed Curlew is estimated to be around 8-10 years in the wild.

2. Where can I spot the Bristle-thighed Curlew during the winter?

The Bristle-thighed Curlew is known to winter exclusively in the Hawaiian Islands, making it a rare and special visitor to these tropical islands. It can be found on all the major Hawaiian islands during the winter months.

3. Why is it called the Bristle-thighed Curlew?

The Bristle-thighed Curlew gets its name from the distinct bristles or feathers that can be seen on its upper thighs, which serve various purposes in courtship displays and territorial defense.